There was no script. The actors were given a summary of the movie and their characters and the rest was improvization.
Duplass wrote a 10-page outline, instead of a script, that allowed for significant improvisation during shooting.
This film was financed by Netflix without even seeing a script.
Like most of the film, the part where Duplass and Paulson said the same beer at the same time in the liquor store was unscribed. Duplass called the moment a "wonderful accident."